Shuttering Clutch

I recently purchased a 1998 TJ with about 98K miles. The clutch seems to be really tight when depressing. I was told that a new high pressure clutch was installed.

The clutch seemed to be leaking off the pressure and making it difficult to shift in and/or out of gear when I stopped at a traffic light, even though no leakage is found. I though it was a bad internal seal in the hydraulics. So, I replaced the complete hydraulic system (kit). The shifting issue stopped but it still seems to require more then normal pressure to depress the clutch to the floor.

When I let the clutch out (while in first gear) the Jeep like shutters a bit while engaging. It only seems to shutter upon starting to move and it normal in all other gears.

I am looking towards having to replace the complete clutch because of the shuttering.

Does anyone have any input to other options?

Are the RPMs dropping too low? Maybe you just need to give it more gas.